| With the rapid development of national economy, the demand of theinfrastructure construction, such as highway, bridges and high-speed rail and soon, is higher and higher. Engineering machinery as an important equipment ofthe construction of infrastructure, the performance of its products directlyaffects the construction process, the engineering quality and funding. Ripper isas an important component part of bulldozer, the stand or fall of its performancedirectly affects the working efficiency of the bulldozer. The operational abilityof traditional ripper is limited by the factors of its own weight, attachmentcoefficient and the ground condition, its operation efficiency is low, and thethrust force of ripper tooth produced by the oil cylinder is small, so thetraditional ripper is not suitable for the occasion of rock and hard soil. Theimpact ripper as a new type of vehicle equipment, its working efficiency isgreatly improved, but the new hydraulic hammer impacts on ripper column withthe frequency of the hundreds of times per minute, thus it causes the vibrationand fatigue damage of the gear lever, so this article is as the type of impactedripper of SD42-3bulldozer an object to study the fatigue characteristics of thegear lever from the perspective of theory and finite element simulation, thecontents include the following aspects:(1)It is researched fatigue strength of the gear lever of the new type ripperon typical working conditions with the theoretical basis of allowable stress-stress ratio method and limit state-stress amplitude method, the theoreticalresults is compared with the corresponding allowable values (limit state-stressamplitude method is the designed range of the ultimate stress), to judge whetherthe gear lever is fatigue failure or not.(2)It is researched the allowable stress-stress ratio method and limit state-stress amplitude method on the basis of the calculation results in differentfatigue strength design theory and on the standard of the maximum safetydegree, so it knows which is suitable and scientific for construction machineryin the design theory of fatigue. (3)It is established three-dimensional entity model of the impacted typeripper of the SD42-3bulldozer based on the limited element softwaresolidworks, and the model is imported to ANSYS Workbench to analysisfatigue of its whole structure under the three typical conditions, then theanalysis result is compared with the calculation results of the optimal theory offatigue design, to verify this theory is scientific and applicable.(4)It is to dynamics analysis on the impacted type ripper on the basis of theanalysis of dynamics, so it is provided some useful mechanism base for thedynamic response analysis and reducing vibration study of the impacted typeripper. |
